270 Secchi and Fay e on the Sun. — Observations by Ghacdmac. 



SECCHI AND FAYE ON THE SUN.— OBSERVATIONS 

 BY CHACORNAC. 



M. Faye communicates to the French Academy* a letter 

 received by him from Father Secchi of the Roman Observatory, 

 on the constitution of the sun, and we proceed to extract the 

 most important remarks in the epistle of the former, and the 

 comments of the latter. 



Father Secchi considers that Carrington' s researches indicate 

 the sun to be either altogether fluid, or, at any rate, much more 

 so than might have been expected from the tenuity of his 

 photosphere, or luminous envelope; and from this state of things 

 he conceives a strong and permanent supply of heat may arise 

 through the caloric disengaged by matter passing from the 

 liquid to the crystalline or vesicular condition, and also from the 

 heat disengaged in processes of dissociation, such as we have 

 explained in former numbers detailing the experiments of St. 

 Claire Deville. He agrees with M. Faye that the sun's layer 

 of transparent atmosphere may be regarded as of moderate 

 thickness, but of considerable refractive power. Such a view 

 would coincide with the observations of Mr. Carrington, who has 

 shown systematic deviations in spots moving towards the sun's 

 margin which might be due to solar refraction. 



Father Secchi finds the bodies known as willow leaves or 

 rice grains all over the sun's surface, but scattered and ranged 

 in a convergent manner towards the centre of the nuclei of 

 spots, and also in the contour of the penumbrse and in their 

 interior, giving rise to the well known serrated appearance. 



Recently he observed a bright white line which divided a 

 nucleus, break itself up into willow leaves on the grey bed of 

 the penumbra. Viewed from any point in the sun the willow 

 leaves must have enormous dimensions, far exceeding those of 

 the cumulus clouds that float in our atmosphere. But our 

 cumuli have rounded forms, while the objects in the sun are 

 elongated. Can this, he asks, result from the movement of 

 transport towards the centre of the spots and from the ten- 

 dency to fill them up ? He thinks that inquiry into the consti- 

 tution of other bodies may elucidate the phenomena of the sun, 

 and he confirms Mr. Huggins' discovery of the gaseous spectrum 

 afforded by the Orion nebula. 



In commenting on Father Secchi' s letter, M. Faye alludes 

 to the labours of De la Rue, Balfour Stewart, and Loewy, which 

 taken in conjunction with those of Carrington, confirm the 

 opinions of Wilson and Herschel and justify his (M. Faye's) 



* See Comptes Mendus, 1865, No. 10. 



